Inlet Valve Throttling and the Effects of Mixture Preparation and Turbulence on the Exhaust Gas Emissions of a Spark Ignition Engine

Abstract

SYNOPSIS. Mixture quality and turbulence in the isolated cylinder of a multi-cylinder spark ignition engine were changed by the method of mixture preparation in the induction tract and by the increase of mixture flow velocity through the valve aperture which was varied by the change of the full lift of the inlet valve. The fuel consumption and the mass rates of the emissions of carbon monoxide, nitric oxide and hydrocarbons of the engine when controlled with a conventional throttle are compared with those of the valve throttled engine. The employment of exhaust gas recirculation is shown to have a decisive effect on the comparison and to be essential for low emissions from a valve throttled engine.